Dilator sheath set

ABSTRACT

This disclosure discusses various methods and devices for providing multiple types of indicators to be used with a sheath set. One type of indicator indicates the linear position and alignment of each of the sheaths within the sheath set, and another type of indicator indicates the rotational position and alignment of the sheaths. Both types of indicators may be included on the ends of the sheath set proximal to the user outside the patient&#39;s vasculature, thereby informing the user of the sheath set of the linear and rotational position and alignment of the ends of the inner and outer sheaths within the vasculature.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to sheaths, including methodsfor using sheaths for separating tissue in a patient, and morespecifically, to techniques for separating tissue attached to leads in apatient's vascular system.

BACKGROUND

Surgically implanted cardiac pacing systems, such as pacemakers anddefibrillators, play an important role in the treatment of heartdisease. In the 50 years since the first pacemaker was implanted,technology has improved dramatically, and these systems have saved orimproved the quality of countless lives. Pacemakers treat slow heartrhythms by increasing the heart rate or by coordinating the heart'scontraction for some heart failure patients. Implantablecardioverter-defibrillators stop dangerous rapid heart rhythms bydelivering an electric shock.

Cardiac pacing systems typically include a timing device and a lead,which are placed inside the body of a patient. One part of the system isthe pulse generator containing electric circuits and a battery, usuallyplaced under the skin on the chest wall beneath the collarbone. Toreplace the battery, the pulse generator must be changed by a simplesurgical procedure. Another part of the system includes the wires, orleads, which run between the pulse generator and the heart. In apacemaker, these leads allow the device to increase the heart rate bydelivering small timed bursts of electric energy to make the heart beatfaster. In a defibrillator, the lead has special coils to allow thedevice to deliver a high-energy shock and convert potentially dangerousrapid rhythms (ventricular tachycardia or fibrillation) back to a normalrhythm. Additionally, the leads may transmit information about theheart's electrical activity to the pacemaker.

For both of these functions, leads must be in contact with heart tissue.Most leads pass through a vein under the collarbone, and the veinconnects to the right side of the heart (right atrium and rightventricle). In some cases, a lead is inserted through a vein and guidedinto a heart chamber where it is attached with the heart. In otherinstances, a lead is attached to the outside of the heart. To remainattached to the heart muscle, most leads have a fixation mechanism, suchas a small screw and/or hooks at the end.

Within a relatively short time after a lead is implanted into the body,the body's natural healing process forms scar tissue along the lead andpossibly at its tip, thereby fastening it even more securely in thepatient's body. Leads usually last longer than the batteries that powerthe device(s); so leads are simply reconnected to each new pulsegenerator (battery) at the time of replacement. Although leads aredesigned to be implanted permanently in the body, occasionally theseleads must be removed, or extracted. Leads may be removed from patientsfor numerous reasons, including but not limited to, infections, leadage, lead malfunction, and lead obsolescence due to device upgrades.

Removal or extraction of the lead may be difficult. As mentioned above,the body's natural healing process forms scar tissue over and along thelead, and possibly at its tip, thereby encasing at least a portion ofthe lead and fastening it even more securely in the patient's body. Inaddition, the lead and/or tissue may become attached to the vasculaturewall. Both results may, therefore, increase the difficulty of removingthe leads from the patient's vasculature.

A variety of tools have been developed to make lead extraction safer andmore successful. Current lead extraction techniques include mechanicaltraction, mechanical devices, and laser devices. Mechanical traction maybe accomplished by inserting a locking stylet into the hollow portion ofthe lead and then pulling the lead to remove it. A mechanical device toextract leads may include a flexible tube called a sheath. One end ofthe sheath passes over the end of the lead outside of the body andenters the vasculature. This end of the sheath then advances over thelead and dilates, separates and/or cuts the surrounding tissue duringadvancement, while the other end of the sheath remains outside of thebody. The end of the sheath that remains outside of the body is the endthat is manipulated and controlled by the user. The mechanical devicemay include one sheath or a set of sheaths, such as an inner sheath andouter sheath which cooperate to separate the scar tissue from other scartissue including the scar tissue surrounding the lead, and in somecases, the sheath(s) may also separate the tissue itself from the lead.Once the lead is separated from the surrounding tissue and/or thesurrounding tissue is separated from the remaining scar tissue, the leadmay be removed from the patient's vasculature using some othermechanical device(s), such as the mechanical traction device previouslymentioned.

SUMMARY

There is a need for a device, method and/or system for a sheath set thatincludes indicators indicative of both the linear and rotationalposition of the sheaths with respect to one another that are visible tothe user while the sheaths are in a patient's vasculature system.

Accordingly, the present disclosure discusses an indicator on an innersheath at a linear position along the inner sheath's longitudinal axissuch that when such indicator is aligned with the proximal end of theouter sheath, the user is informed that distal ends of the inner sheathand the outer sheath are linearly aligned such that the distal end ofthe inner sheath is located within the distal end of the outer sheath.The present disclosure also discusses that the inner sheath can have twohalves, which are the mirror images of each, such that the distal end ofthe inner sheath can be removed from the outer sheath and the originalproximal end can be inserted into the outer sheath such that when thesame or additional indicator is linearly aligned with the now proximalend of the outer sheath, the user is informed that the now distal endsof the inner sheath and the outer sheath are linearly aligned such thatthe distal end of the inner sheath is located at and/or within thedistal end of the outer sheath. Alternatively, the distal end of theouter sheath can be removed from the inner sheath and the originalproximal end of the outer sheath can be inserted over the inner sheathsuch that when the same or additional indicator is linearly aligned withthe now proximal end of the outer sheath, the user is informed that nowdistal ends of the inner sheath and the outer sheath are linearlyaligned such that the distal end of the inner sheath is located atand/or within the distal end of the outer sheath.

The present disclosure also discusses having further indicators alongthe longitudinal axis of the inner sheath and outer sheath to indicatethe rotational position of each of the inner sheath and outer sheath, aswell as the rotational alignment of the inner sheath and with respect tothe outer sheath. Providing both types of indicators—one type ofindicator indicative of linear position and alignment and another typeof indicator indicative of rotational position and alignment—on ortowards the halves or ends of the inner sheath proximal to the userand/or outside the patient's vasculature, informs the user of the innersheath of the linear and rotational positions and alignment of the innersheath within the patient's vasculature. Also, providing an indicatorindicative of rotational position and alignment of the outer sheath onor toward the proximal end of the outer sheath that is outside thepatient's vasculature, informs the user of the outer sheath of therotational position of the distal end of the outer sheath within thepatient's vasculature. Providing the linear position indicator androtational position indicator on the proximal end inner sheath incombination with providing the rotational position indicator on theproximal end of the outer sheath, informs the user of the sheath set ofthe linear position and alignment of the inner and outer sheathsrelative to one another, the rotational position of each of the innerand outer sheaths, and the possible rotational alignment of the innerand outer sheaths relative to one another for the halves or ends of theinner sheath and outer sheath distal to the user and/or inside thepatient's vasculature.

This linear and rotational position information is helpful to the user,particularly when the user is using the sheath set to navigate curved ortortuous paths of the patient's vasculature. Such information is alsohelpful to the user when the distal ends of the inner sheath and/orouter sheath are beveled such that the face of the distal end is angled,thereby creating two edges at the intersection of the face and theexterior surface of the outer sheath. In comparison to one another, onebeveled edge (aka heel) is more proximal to the other beveled edge (akatip), and one beveled edge (aka tip) is more distal to the other bevelededge (aka heel). Knowing the position of the proximal beveled edgeand/or distal beveled edge of the inner sheath and/or outer sheath ishelpful to the user when using the sheath set to navigate curved ortortuous paths of the patient's vasculature because the user may preferto have the distal beveled edge(s) on the interior of the curvedvasculature and the proximal beveled edge(s) on the exterior of thecurved vasculature to reduce the likelihood of puncturing thevasculature as the sheath set passes therethough. Accordingly, it may bedesirable for the indicators indicative of the rotational position ofthe inner sheath and outer sheath to be aligned with the proximalbeveled edge(s) and/or distal beveled edge(s) along the longitudinalaxes of the inner sheath and outer sheath.

A method of separating tissue surrounding a lead within a blood vessel,the method comprising the steps of: (a) inserting a sheath set over aproximal end of a lead within a blood vessel, the sheath set comprising:an outer sheath comprising a proximal end, a beveled distal end, a lumenbetween the proximal end and the beveled distal end, an exteriorsurface, and a longitudinal axis, wherein the beveled distal end forms abeveled proximal edge with the exterior surface of the outer sheath anda beveled distal edge with the exterior surface of the outer sheath,wherein the outer sheath further comprises a rotational positionindicator on the exterior surface of the outer sheath and along thelongitudinal axis of the outer sheath, wherein the rotational positionindicator is aligned with the beveled distal edge; and an inner sheathcomprising a first beveled end, a second beveled end, a center betweenthe first beveled end and the second beveled end, an exterior surface,and a longitudinal axis, the inner sheath located at least partiallywithin the lumen of the outer sheath, wherein the first beveled endforms a first proximal edge with the exterior surface of the innersheath and a first distal edge with the exterior surface of the innersheath, wherein the second beveled end forms a second proximal edge withthe exterior surface of the inner sheath and a second distal edge withthe exterior surface of the inner sheath, wherein the first proximaledge and the second proximal edge are proximate the center relative tothe first distal edge and the second distal edge, respectively, whereinthe inner sheath further comprises a rotational position indicator onthe exterior surface of the inner sheath and along the longitudinal axisof the inner sheath, wherein the rotational position indicator isaligned with the first beveled distal edge and the second beveled distaledge, and a first indicator on the exterior surface of the inner sheathindicative, wherein the first indicator indicates the first beveled endof the inner sheath is aligned with the beveled distal end of the outersheath when the first indicator is aligned with the proximal end of theouter sheath, and a second indicator on the exterior surface of theinner sheath, wherein the second indicator indicates the second beveledend of the inner sheath is aligned with the beveled distal end of theouter sheath when the second indicator is aligned with the proximal endof the outer sheath; (b) aligning the first indicator of the innersheath with the proximal end of the outer sheath; (c) aligning therotational position indicator of the inner sheath with the rotationalposition indicator of the outer sheath, thereby creating an alignedposition for the inner sheath and outer sheath; (d) advancing the innersheath and the outer sheath concurrently in the aligned position overthe lead in the blood vessel; and (e) further advancing and rotating theinner sheath such that the first beveled end of the inner sheath extendsdistally of the beveled distal end of the outer sheath.

The method may also include the steps of retracting the inner sheathwithin the outer sheath to the aligned position, advancing the innersheath and the outer sheath concurrently in the aligned position overthe lead in the blood vessel, and further advancing and rotating theinner sheath such that the first beveled end of the inner sheath extendsdistally of the beveled distal end of the outer sheath. The method mayfurther and/or alternatively include extending the outer sheath distallyto the inner sheath, such that the inner sheath is retracted into theouter sheath.

A device, according to this disclosure, may include a sheath set forinsertion into a blood vessel, the sheath set comprising: an outersheath comprising a proximal end, a beveled distal end, a lumen betweenthe proximal end and the beveled distal end, an exterior surface, and alongitudinal axis, wherein the beveled distal end forms a beveledproximal edge with the exterior surface of the outer sheath and abeveled distal edge with the exterior surface of the outer sheath,wherein the outer sheath further comprises a rotational positionindicator on the exterior surface of the outer sheath and along thelongitudinal axis of the outer sheath, wherein the rotational positionindicator is aligned with the beveled distal edge; and an inner sheathcomprising a first beveled end, a second beveled end, a center betweenthe first beveled end and the second beveled end, an exterior surface,and a longitudinal axis, the inner sheath located at least partiallywithin the lumen of the outer sheath, wherein the first beveled endforms a first proximal edge with the exterior surface of the innersheath and a first distal edge with the exterior surface of the innersheath, wherein the second beveled end forms a second proximal edge withthe exterior surface of the inner sheath and a second distal edge withthe exterior surface of the inner sheath, wherein the first proximaledge and the second proximal edge are proximate the center relative tothe first distal edge and the second distal edge, respectively, whereinthe inner sheath further comprises a rotational position indicator onthe exterior surface of the inner sheath and along the longitudinal axisof the inner sheath, wherein the rotational position indicator isaligned with the first beveled distal edge and the second beveled distaledge, and a first indicator on the exterior surface of the inner sheathindicative of the first beveled end of the inner sheath being alignedwith the beveled distal end of the outer sheath when the first indicatoris aligned with the proximal end of the outer sheath, and a secondindicator on the exterior surface of the inner sheath indicative of thesecond beveled end of the inner sheath being aligned with the beveleddistal end of the outer sheath when the second indicator is aligned withthe proximal end of the outer sheath.

A device, according to this disclosure, may also include a sheath setfor insertion into a blood vessel, the sheath set comprising: an outersheath comprising a proximal end, a beveled distal end, a lumen betweenthe proximal end and the beveled distal end, an exterior surface, and alongitudinal axis, wherein the beveled distal end forms a beveledproximal edge with the exterior surface of the outer sheath and abeveled distal edge with the exterior surface of the outer sheath,wherein the outer sheath further comprises a rotational positionindicator on the exterior surface of the outer sheath and along thelongitudinal axis of the outer sheath, wherein the rotational positionindicator is aligned with the beveled distal edge; and an inner sheathcomprising a first beveled end, a second beveled end, a center betweenthe first beveled end and the second beveled end, an exterior surface,and a longitudinal axis, the inner sheath located at least partiallywithin the lumen of the outer sheath, wherein the first beveled endforms a first proximal edge with the exterior surface of the innersheath and a first distal edge with the exterior surface of the innersheath, wherein the second beveled end forms a second proximal edge withthe exterior surface of the inner sheath and a second distal edge withthe exterior surface of the inner sheath, wherein the first proximaledge and the second proximal edge are proximate the center relative tothe first distal edge and the second distal edge, respectively, whereinthe inner sheath further comprises a rotational position indicator onthe exterior surface of the inner sheath and along the longitudinal axisof the inner sheath, wherein the rotational position indicator isaligned with the first beveled distal edge and the second beveled distaledge, and indicator on the exterior surface of the inner sheath andlocated at the center, wherein the indicator indicates the first beveledend of the inner sheath is aligned with the beveled distal end of theouter sheath when the indicator is aligned with the proximal end of theouter sheath, and wherein the indicator indicates the second beveled endof the inner sheath is aligned with the beveled distal end of the outersheath when the indicator is aligned with the proximal end of the outersheath.

The devices may further include an at least one pair of indicatorscomprising two markings having a space therebetween, wherein the spaceindicates the first beveled end of the inner sheath is aligned with thebeveled distal end of the outer sheath when the proximal end of theouter sheath is aligned with the space. Also, the at least one pair ofindicators may be aligned with the rotational position indicator on theexterior surface of the inner sheath.

A device, according to this disclosure, may also include a sheathcomprising a first beveled end, a second beveled end, a center betweenthe first beveled end and the second beveled end, an exterior surface,and a longitudinal axis, wherein the first beveled end forms a firstproximal edge with the exterior surface of the inner sheath and a firstdistal edge with the exterior surface of the inner sheath, wherein thesecond beveled end forms a second proximal edge with the exteriorsurface of the inner sheath and a second distal edge with the exteriorsurface of the inner sheath, wherein the first proximal edge and thesecond proximal edge are proximate the center relative to the firstdistal edge and the second distal edge, respectively, wherein the innersheath further comprises a rotational position indicator on the exteriorsurface of the inner sheath and along the longitudinal axis of the innersheath, wherein the rotational position indicator is aligned with thefirst beveled distal edge and the second beveled distal edge, and afirst indicator on the exterior surface of the inner sheath located afirst predetermined distance from the first beveled end of the innersheath, and a second indicator on the exterior surface of the innersheath located a second predetermined distance from the second beveledend of the inner sheath, wherein the first predetermined distance andthe second predetermined distance are either the same or different.

The phrases “at least one”, “one or more”, and “and/or” are open-endedexpressions that are both conjunctive and disjunctive in operation. Forexample, each of the expressions “at least one of A, B and C”, “at leastone of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B,or C” and “A, B, and/or C” means A alone, B alone, C alone, A and Btogether, A and C together, B and C together, or A, B and C together.When each one of A, B, and C in the above expressions refers to anelement, such as X, Y, and Z, or class of elements, such as X₁-X_(n),Y₁-Y, and Z₁-Z_(o), the phrase is intended to refer to a single elementselected from X, Y, and Z, a combination of elements selected from thesame class (e.g., X₁ and X₂) as well as a combination of elementsselected from two or more classes (e.g., Y₁ and Z_(o)).

The term “a” or “an” entity refers to one or more of that entity. Assuch, the terms “a” (or “an”), “one or more” and “at least one” may beused interchangeably herein. It is also to be noted that the terms“comprising”, “including”, and “having” may be used interchangeably.

A “catheter” is a tube that can be inserted into a body cavity, duct,lumen, or blood vessel, such as the vasculature system. In most uses, acatheter is a relatively thin, flexible tube (“soft” catheter), thoughin some uses, it may be a larger, solid, less flexible—but possiblystill flexible—catheter (“hard” catheter). Additionally, the cathetermay also have a working tip, such as a sharp blade to cut the bodilymaterial (e.g., plaque) or a laser to ablate the bodily material, withwhich it contacts.

The term “indicator” as used herein is a distinguishing mark thatprovides an indication of position, direction and/or orientation. Theindicator may be visual, non-visual or a combination thereof. An exampleof a visual indicator includes a printed mark perceptible to the humaneye. An example of a non-visual indicator includes a tactile indicator,such as protrusion on and/or depression in a device such that the userof the device feels the indicator. Another example of a tactileindicator is an audible indicator perceptible to the human ear. Afurther type of non-visual indicator may include a radiopaque marker,which may require the use of visual aid equipment, such as that usingultrasound, x-ray, optical, magnetic, electro-magnetic, etc. technology.Other types of visual and/or non-visual indicators may include a markthat has light reflective optical property that differs from that ofdevice associated with the mark, a magnet that creates a magnetic field,and a radio frequency parameter associated with the markers (which canbe an active and/or passive Radio Frequency-Identification (“RFID”)tag). The indicator may include one mark or a plurality of marks.Accordingly, the term “indicia” as used herein shall refer to aplurality of distinguishing marks that provide an indication ofposition, direction and/or orientation. An indicator of position caninclude relative position.

A “lead” as used herein is a conductive structure, typically anelectrically insulated coiled wire. The electrically conductive materialmay be any conductive material, with metals and intermetallic alloyscommon. The outer sheath of insulated material is biocompatible and biostable (e.g., non-dissolving in the body) and generally includes organicmaterials such as polyurethane and polyimide. Lead types include, by wayof non-limiting example, epicardial and endocardial leads. Leads arecommonly implanted into a body percutaneously or surgically.

The term “means” as used herein shall be given its broadest possibleinterpretation in accordance with 35 U.S.C. Section 112(f). Accordingly,a claim incorporating the term “means” shall cover all structures,materials, or acts set forth herein, and all of the equivalents thereof.Further, the structures, materials or acts and the equivalents thereofshall include all those described in the summary of the invention, briefdescription of the drawings, detailed description, abstract, and claimsthemselves.

The term “sheath” as used herein shall mean a tubular structure, such asa catheter, having a lumen therethrough.

The term “sheath set” includes two or more sheaths, wherein one sheathis capable of being inserted within another sheath.

A “surgical implant” is a medical device manufactured to replace amissing biological structure, support, stimulate, or treat a damagedbiological structure, or enhance, stimulate, or treat an existingbiological structure. Medical implants are man-made devices, in contrastto a transplant, which is a transplanted biomedical tissue. In somecases implants contain electronics, including, without limitation,artificial pacemaker, defibrillator, electrodes, and cochlear implants.Some implants are bioactive, including, without limitation, subcutaneousdrug delivery devices in the form of implantable pills or drug-elutingstents.

The term “tissue” as used herein shall mean an aggregate of similarcells forming a biological structural.

The term “vasculature” or “vascular system” as used herein shall mean ablood vessel or network of blood vessels within patient's circulatorysystem or any part thereof, including network of arteries, veins andcapillaries that convey blood.

It should be understood that every maximum numerical limitation giventhroughout this disclosure is deemed to include each and every lowernumerical limitation as an alternative, as if such lower numericallimitations were expressly written herein. Every minimum numericallimitation given throughout this disclosure is deemed to include eachand every higher numerical limitation as an alternative, as if suchhigher numerical limitations were expressly written herein. Everynumerical range given throughout this disclosure is deemed to includeeach and every narrower numerical range that falls within such broadernumerical range, as if such narrower numerical ranges were all expresslywritten herein.

The preceding is a simplified summary of the disclosure to provide anunderstanding of some aspects of the disclosure. This summary is neitheran extensive nor exhaustive overview of the disclosure and its variousaspects, embodiments, and configurations. It is intended neither toidentify key or critical elements of the disclosure nor to delineate thescope of the disclosure but to present selected concepts of thedisclosure in a simplified form as an introduction to the more detaileddescription presented below. As will be appreciated, other aspects,embodiments, and configurations of the disclosure are possibleutilizing, alone or in combination, one or more of the features setforth above or described in detail below

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated into and form a part of thespecification to illustrate several examples of the present disclosure.These drawings, together with the description, explain the principles ofthe disclosure. The drawings simply illustrate preferred and alternativeexamples of how the disclosure may be made and used and are not to beconstrued as limiting the disclosure to only the illustrated anddescribed examples. Further features and advantages will become apparentfrom the following, more detailed, description of the various aspects,embodiments, and configurations of the disclosure, as illustrated by thedrawings referenced below.

FIG. 1 is a top view of an embodiment of a sheath set including an innersheath having one end disposed within an outer sheath and the other endof which is extending from the outer sheath;

FIG. 2 is a bottom view of an embodiment of a sheath set including aninner sheath having one end disposed within an outer sheath and theother end of which is extending from the outer sheath;

FIG. 3 is a side elevation view of an embodiment of an outer sheath;

FIG. 4 is side elevation view of an embodiment of an inner sheath;

FIG. 5 is a bottom view of an embodiment of an outer sheath;

FIG. 6 is a bottom view of an embodiment of an inner sheath;

FIG. 7 is an enlarged view of one end of the outer sheath;

FIG. 8 is an enlarged view of one end of the outer sheath; and

FIG. 9 is an enlarged view of one end of the inner sheath.

It should be understood that the drawings are not necessarily to scale.In certain instances, details that are not necessary for anunderstanding of the disclosure or that render other details difficultto perceive may have been omitted. It should be understood, of course,that the disclosure is not necessarily limited to the particularembodiments illustrated herein.

DETAILED DESCRIPTION

Before any embodiments of the disclosure are explained in detail, it isto be understood that the disclosure is not limited in its applicationto the details of construction and the arrangement of components setforth in the following description or illustrated in the followingdrawings. The disclosure is capable of other embodiments and of beingpracticed or of being carried out in various ways. Also, it is to beunderstood that the phraseology and terminology used herein is for thepurpose of description and should not be regarded as limiting. The useof “including,” “comprising,” or “having” and variations thereof hereinis meant to encompass the items listed thereafter and equivalentsthereof as well as additional items.

With reference to FIG. 1 and FIG. 2, an exemplary sheath set 100 isdepicted. The sheath set includes an inner sheath 104 and an outersheath 108. Both the inner sheath 104 and the outer sheath 108 have twoends, a longitudinal axis, a lumen extending therethough along thelongitudinal axis between the two ends, and an exterior surface.Depending upon the orientation of the inner sheath 104 and the outersheath 108, the ends may be referred to as either a proximal end or adistal end. The proximal end generally refers to the end closest theuser of the inner sheath 104 and the outer sheath 108, and the distalend generally refers to the end furthest from the user. In use, theproximal ends of the sheath set typically remain outside the patient'svasculature, and the distal ends of the sheath set typically enter thepatient's vasculature.

The inner sheath 104 and the outer sheath 108 may preferably beconstructed of a rigid and flexible biocompatible material, such asstainless steel or biocompatible polymers, using an extrusion process.An example of a biocompatible polymer is polypropylene. Additives, suchas polyolefin elastomers, may also be combined with the polypropylene toobtain the desired rigidity, flexibility, fracture toughness and/orimpact strength of the sheaths. Additionally, radiopaque material mayfurther be added to the blend of biocompatible polymer. Adding theradiopaque material to the blend will allow a physician to see the innersheath 104 and the outer sheath 108 within the patient's vasculaturewith the aid of visualization equipment, such as that is known in theart (e.g., fluoroscopy).

With reference to FIG. 3, there is depicted a side view of an exemplaryouter sheath 108 having two ends 150, 154. The opposite side view of theouter sheath 108 is not shown. Nevertheless, it is a mirror image ofFIG. 3. Referring to FIG. 7, there is depicted an enlarged view of end150 of the outer sheath 108. The end 150 of the outer sheath 108 istapered, and the face 166 of the end 150 of the outer sheath 108 isgenerally orthogonal to the longitudinal axis of the outer sheath 108.

Referring to FIG. 8, there is depicted an enlarged view of end 154 ofthe outer sheath 108. Similar to end 150, the end 154 of the outersheath 108 is tapered such that the thickness of the wall of the outersheath 108 reduces towards the face 170. However, unlike the end 150,the face 170 of the end 154 is beveled with respect to the longitudinalaxis of the outer sheath 108. Because the face 170 of the end 154 isbeveled, the intersection of the face 170 and the exterior surface ofthe outer sheath 108 forms an acute angle, thereby creating an edge 178.Additionally, the intersection of the face 170 and the exterior surfaceof the outer sheath 108 forms an obtuse angle, thereby creating an edge182. In comparison to the edge 182, the edge 178 is further distally ofthe center and of the end 150 of the outer sheath 108. That is, the edge182 is located more proximal the center and the end 150 of the outersheath 108 in comparison to the edge 178. Accordingly, the edge 182 maybe referred to as a proximal edge, a beveled proximal edge, or a beveledproximal edge portion, and the edge 178 may be referred to as a distaledge, a beveled distal edge, or a beveled distal edge portion. That is,the distal edge 178 acts as a tip of the face 170, and proximal edge 182acts as a heel of the face 170. Accordingly, distal edge 178 acts as atip for the outer sheath 108. Furthermore, the use of the terminologyfor proximal edge and distal edge may be reversed in the event that theorientation of the outer sheath 108 is such that end 154 is locatedcloser to the user than the end 150. Moreover, although FIGS. 3, 7 and 8depict and discuss one orthogonally shaped end 150 and one beveled end154, both ends of the outer sheath 108 may be orthogonal or both endsmay be beveled.

Referring to FIG. 5, there is depicted a bottom view of an exemplaryouter sheath 108 having two ends 150, 154. This figure illustratesindicator 134 positioned along the longitudinal axis of the outer sheath108. As discussed in more detail below, indicator 134 is used todetermine the rotational position of the outer sheath 108 within apatient's vasculature, as well as the rotational alignment of the outersheath 108 with respect to the inner sheath 104. The indicator 134depicted in FIG. 5 is not only positioned along the longitudinal axis ofthe outer sheath 108, but the indicator 134 is also aligned with theedge 178 of the distal end 154 of the outer sheath 108. As discussedabove with respect to FIG. 8, edge 178 is the most distal edge of thebeveled face 170. Positioning indicator 134 in longitudinal alignmentwith the distal edge 178, informs the user (i.e., clinician) of theouter sheath 108 of the position of tip of end 154 located within thepatient's vasculature because the indicator 134 is located on the outersheath 108 at or towards the end 150 located proximal to the user and/oroutside the patient's vasculature. This may be particularly helpful whenthe user is navigating the outer sheath 108, either alone or inconjunction with the inner sheath 104, through a curved or tortuousportion of the patient's vasculature. For example, assuming a portion ofthe vasculature is curved, there will be an interior segment and anexterior segment of the curved vasculature. And it may be desirable forthe beveled distal edge 178 of the outer sheath 108 to pass through thecurved portion of the vasculature along the interior segment rather thanthe exterior segment, thereby reducing the likelihood that the beveleddistal edge 178 will rupture the vasculature as it passes therethrough.That is, it may be desirable for beveled proximal edge 182 of the outersheath 108 to pass through the vasculature along the exterior curvedsegment and the beveled distal edge 178 of the outer sheath 108 to passthrough the interior segment. If so, the user would navigate the outersheath 108 with the indicator 134 aligned with the interior segment ofthe curved vascular portion. Accordingly, providing indicator 134 on theouter sheath 108 informs its user of the position of edge 178 of end 154located within the patient's vasculature because the indicator 134, inaddition to being located on the distal end of the outer sheath 108, isat, on, or towards the end 150 located proximal to the user and/oroutside the patient's vasculature so that such indicator 134 is visibleto the user during the procedure while the other distal end of the outersheath 108 is located within patient's vasculature.

FIG. 5 depicts the indicator 134 in alignment with the distal bevelededge 178 of the end 154 of the outer sheath 108. However, the indicator134 may alternatively be aligned with the proximal beveled edge 182 ofthe outer sheath 108. If so, positioning indicator 134 in alignment withthe proximal beveled edge 182 of the distal end 154, informs the user(i.e., clinician) of the outer sheath 108 of the position of edge 182 ofend 154 located within the patient's vasculature by looking at theindicator 134, which is also located on the outer sheath 108 at ortowards the end 150 located proximal the user and/or outside thepatient's vasculature. In such instance, it may be desirable forproximal edge 182 of the outer sheath 108 to pass through thevasculature along the exterior curved segment and the distal edge 178 ofthe outer sheath 108 to pass through the interior segment. If so, theuser would navigate the outer sheath 108 with the indicator 134 alignedwith the exterior segment of the curved vascular portion.

The indicator 134 in FIG. 5 is depicted as a solid line between the ends150, 154 on the exterior surface of the outer sheath 108. However, theindicator may not be a solid line. For example, the indicator mayalternatively include a series of broken lines, a series of dots, aseries of lines and dots and/or a combination of lines, dots and othercharacters that are positioned in alignment with the longitudinal axisof the outer sheath 108 and/or in alignment with the proximal bevelededge 182 or distal beveled edge 178 of end 154. Additionally, the outersheath may have multiple indicators aligned with the longitudinal axisof the outer sheath 108. For example, the outer sheath 108 may includeone type of indicator positioned along its longitudinal axis that alignswith the proximal beveled edge 182 and another type of indicatorpositioned along its longitudinal axis that aligns with the distalbeveled edge 178. Furthermore, the outer sheath 108 may include a thirdtype of indicator positioned along its longitudinal axis that alignswith another reference point for the end 154. For example, the thirdtype of indicator may indicate the mid-point of the face 170 of the end154.

With reference to FIG. 4, there is depicted a side view of an exemplaryinner sheath 104 having two ends 158, 162. The opposite side view of theinner sheath 104 is not shown. Nevertheless, it is a mirror image ofFIG. 4. Referring to FIG. 9, there is depicted an enlarged view of end162 of the inner sheath 104. Although only end 162 will be discussed, itshall be understood that end 158 may have the same configuration as end162. The end 162 of the inner sheath 104 is tapered. The end 162includes a face 174 that is beveled with respect to the longitudinalaxis of the inner sheath 104. Because the face 174 of the end 162 isbeveled, the intersection of the face 174 and the exterior surface ofthe inner sheath 104 forms an acute angle, thereby creating an edge 186.Additionally, the intersection of the face 174 and the exterior surfaceof the inner sheath 104 forms an obtuse angle, thereby creating an edge190. In comparison to the edge 190, the edge 186 is further distally ofthe center and of the end 158 of the inner sheath 104. That is, the edge190 is located more proximal the center and the end 158 of the innersheath 104 in comparison to the edge 186. Accordingly, the edge 190 maybe referred to as a proximal edge, a beveled proximal edge, or a beveledproximal edge portion, and the edge 186 may be referred to as a distaledge, a beveled distal edge, or a beveled distal edge portion. That is,the distal edge 186 acts as a tip of the face 174, and proximal edge 190acts as a heel of the face 174. Accordingly, distal edge 186 acts as atip for the inner sheath 104. Furthermore, the use of the terminologyfor proximal edge and distal edge may be reversed in the event that theorientation of the inner sheath 104 is such that end 162 is locatedcloser to the user than the end 158. Moreover, although FIGS. 3 and 8depict and discuss two beveled ends 158, 162, one or both ends of theinner sheath 104 may be orthogonally shaped.

Continuing to refer to FIG. 4, there are depicted two indicators, namelyindicator 112 and indicator 116 on the exterior surface of the innersheath 104. Indicator 112 and indicator 116 provide a user with anindication of the linear position and alignment of the inner sheath 104with respect to the outer sheath 108. Specifically, when the innersheath 104 is located within the lumen of the outer sheath 108 andindicator 112 on the inner sheath 104 is linearly aligned with the end150 of the outer sheath 108, the indicator 112 indicates to the userthat the end 162 of the inner sheath 104 is linearly aligned with theend 154 of the outer sheath 108. When the end 162 of the inner sheath104 is linearly aligned with the end 154 of the outer sheath 108, theend 162 is located at the end 154 of the outer sheath, is within theouter sheath 134, and is not extending beyond the distal end 154 of theouter sheath 108. Additionally, when the inner sheath 104 is locatedwithin the lumen of the outer sheath 108 and indicator 112 on the innersheath 104 is not linearly aligned with the end 150 of the outer sheath108 such that the all of the indicator 112 is entirely visible to theuser, then the indicator 112 indicates to the user that the end 162 ofthe inner sheath 104 is not linearly aligned with the end 154 of theouter sheath 108 and the end 162 of the inner sheath 104 is locatedproximally of the end 154 of the outer sheath 108 and potentially withinthe outer sheath 108. Furthermore, when the inner sheath 104 is locatedwithin the lumen of the outer sheath 108 and indicator 112 on the innersheath 104 is not linearly aligned with the end 150 of the outer sheath108 such that the entire indicator 112 is not at all visible to theuser, then the indicator 112 indicates to the user that the end 162 ofthe inner sheath 104 is not linearly aligned with the end 154 of theouter sheath 108 and the end 162 of the inner sheath 104 is protrudingbeyond the end 154 of the outer sheath 108.

Similarly, when the inner sheath 104 is located within the lumen of theouter sheath 108 and indicator 116 on the inner sheath 104 is linearlyaligned with the end 150 of the outer sheath 108, the indicator 116indicates to the user that the end 158 of the inner sheath 104 islinearly aligned with the end 154 of the outer sheath 108. Indicators112 and 116 on the exterior surface of the inner sheath 104 can also belinearly aligned with end 154 of the outer sheath 134 to indicate thatthe corresponding end 158 or 162 is linearly aligned with end 150 of theouter sheath 134.

Indicator 112 and indicator 116 may each include a single mark or acombination of marks. For example, FIG. 4 illustrates indicator 112 as acombination, particularly a pair of two triangular shaped marks 120, 124spaced apart and facing one another such that the triangularly shapedmarks 120, 124 are mirror images of one another because the apex of eachtriangularly shaped mark 120, 124 face each another. When the innersheath 104 is located within the lumen of the outer sheath 108 and thespace between the two apexes of the triangularly shaped marks 120, 124is linearly aligned with the end 150 of the outer sheath 108, theindicator 112 indicates to the user that the end 162 of the inner sheath104 is linearly aligned with the end 154 of the outer sheath 108.Similarly, FIG. 4 illustrates indicator 116 as a pair of two triangularshaped marks 126, 130 spaced apart and facing one another such that thetriangularly shaped marks 126, 130 are mirror images of one anotherbecause the apex of each triangularly shaped mark 126, 130 face eachanother. When the inner sheath 104 is located within the lumen of theouter sheath 108 and the space between the two apexes of thetriangularly shaped marks 126, 130 is linearly aligned with the end 150of the outer sheath 108, the indicator 116 indicates to the user thatthe end 158 of the inner sheath 104 is linearly aligned with the end 154of the outer sheath 108.

As illustrated in FIG. 2, the triangularly shaped mark 120″ pointstoward the end 150 of the outer sheath 108. The shape, orientation andspace between the triangularly shaped marks 120″, 124″ 126″, 130″,particularly the directional aspect of triangularly shaped mark andtheir spaced apart configuration, provide a user with an intuitive anduseful indicator where to align inner sheath 104 with the outer sheath108 such that ends 158, 162 of the inner sheath 104 linearly align withthe end 154 of the outer sheath 108. However, other type of marks may beused as indicators 112, 116. The marks may have an alternate geometricshapes, such as a circle, oval, ellipse, crescent, curvilinear triangle,quatrefoil, parallelogram, square, rectangle, trapezoid, trapezium,rhombus, pentagon, hexagon, heptagon, octagon, nonagon, and decagon. Themarks may also have other types of shapes or symbols, such as a kite,star, heart, cross, arrow, diamond, etc. Additionally, one indicator,such as indicator 112 may have a pair of marks with the same shape, andthe other indicator, such as indicator 116 may have a pair of marks withthe same shape but different than the shape of the marks for indicator112. Furthermore, the indicator may include a combination of twodifferently shaped marks. Moreover, each mark may have the same color(e.g., red, orange, yellow, green, blue, purple, black, etc.) or acombination of different colors.

As mentioned above, the indicator 112, 116 may include a single markrather than a combination of marks. For example, the indicators 112, 116may include one of the shapes or symbols discussed above. Alternatively,the indicators 112, 116 may include an indicator, such as a line,stripe, bar, etc. Such indicator may have a single color (e.g., red,orange, yellow, green, blue, purple, black, etc.) or a combination ofmultiple colors. Furthermore, any of the indicators discussed above mayhave a particular color, and if multiple indicators are used, suchindicator may have the same or different colors, thereby creating acolor code therefor.

The indicators 112, 116 may include a set of multiple individual marksor multiple sets of marks around the circumference of the inner sheath104 at the same linear position. Having a set of individual marks (e.g.,any combination of 120, 120′ and 120″) or multiple sets of marks providethe user the ability to see the linear position of the inner sheath 104with respect to the outer sheath 108 from multiple rotationalperspectives. Referring to FIGS. 4 and 6, the indicator 112 may includethree sets, wherein each set is a pair of triangularly shaped marks: (1)the first set includes a pair of triangularly shaped marks 120, 124; (2)the second set includes a pair of triangularly shaped marks 120′, 124′;and (3) the third set includes a pair of triangularly shaped marks 120″,124″. Each set of marks may be spaced evenly around the circumference ofthe inner sheath 104 at the same linear distance from one of the ends158, 162. For example, the first, second, and third set of marks may bespaced 120 degrees from each other around the circumference of the innersheath 104. If a fourth set of marks was included as part of theindicator 112, the four sets of marks may be spaced 90 degrees from eachother around the circumference of the inner sheath 104. Similarly, if afifth set of marks was included as part of the indicator 112, the fivesets of marks may be spaced 72 degrees from each other around thecircumference of the inner sheath 104. Including multiple sets of marks,particularly three or more sets of marks, provides the user of thesheath set 100 with constant visualization of the linear orientation ofthe inner sheath 104 relative to the outer sheath. Although the majorityof this paragraph discusses the indicator 112 and its corresponding setsof marks, it shall be understood that the same discussion applies toindicator 116 and its corresponding set of marks, wherein the first setincludes triangularly shaped marks 126, 130; (2) the second set includestriangularly shaped marks 126′, 130′; and (3) the third set includestriangularly shaped marks 126″, 130″.

Referring to FIG. 6, there is depicted a bottom view of an exemplaryinner sheath 104 having two ends 158, 162. This figure illustrates threeindicators 138, 142, 146 positioned along the longitudinal axis of theinner sheath 104. As discussed in more detail below, the threeindicators 138, 142, 146 are used to determine the rotational positionof the inner sheath 104 within the patient's vasculature, as well as therotational alignment of the inner sheath 104 with respect to the outersheath 108. The three indicators 138, 142, 146 depicted in FIG. 6 arenot only positioned along the longitudinal axis of the inner sheath 104,but the three indicators 138, 142, 146 are also aligned with the edge186 of the beveled ends 158, 162 of the inner sheath 104. As discussedabove with respect to FIG. 9, edge 186 is the most distal edge of thebeveled face 174. Positioning indicators 138, 142, 146 in longitudinalalignment with the edge 186, informs the user (i.e., clinician) of theinner sheath 104 of the position of edge 186 for ends 158, 162 locatedwithin the patient's vasculature because the three indicators 138, 142,146 are located on the inner sheath 104 at or towards one of the ends158, 162 located proximal the user and/or outside the patient'svasculature. Accordingly, providing indicators 138, 142, 146 informs theuser of the inner sheath 104 of the position of edge 186 of end 158, 162located within the patient's vasculature because at least some of theindicators 138, 142, 146, in addition to being located on the distal endof the inner sheath 104, is at, on, or towards the opposite end 158, 162located proximal to the user and/or outside the patient's vasculature sothat such indicators 138, 142, 146 is visible to the user during theprocedure while the other distal end of the outer sheath 108 is locatedwithin patient's vasculature.

As discussed above, with respect to the outer sheath 108, it may behelpful to the user when navigating the inner sheath 104, either aloneor in conjunction with the outer sheath 108, through a curved ortortuous portion of the patient's vasculature to know where the distaledge 186 and proximal edge 190 are located with respect to the interiorsegment and the exterior segment of the curved vasculature. It may bedesirable for the distal edge 186 of the inner sheath 104 to passthrough the curved portion of the vasculature along the interior segmentrather than the exterior segment, thereby reducing the likelihood thatthe distal beveled edge 186 will rupture the vasculature as it passestherethrough. That is, it may be desirable for proximal edge 190 of theinner sheath 104 to pass through the vasculature along the exteriorcurved segment and the distal edge 186 of the inner sheath 104 to passthrough the interior segment. If so, the user would navigate the innersheath 104 with the indicators 138, 142, 146 aligned with the interiorsegment of the curved vascular portion.

FIG. 6 depicts the indicators 138, 142, 146 in alignment with the distalbeveled edge 186 of the ends 158, 162 of the inner sheath 104. However,one or all of the indicator 138, 142, 146 may alternatively be alignedwith the proximal beveled edge 190 of the inner sheath 104. If so,positioning indicators 138, 142, 146 in alignment with the proximalbeveled edge 190 of the ends 158, 162, informs the user (i.e.,clinician) of the inner sheath 104 of the position of edge 190 of one ofthe ends 158, 162 located within the patient's vasculature by looking atone or more of the indicators 138, 142, 146, which are also located onthe inner sheath 104 at or towards one of the ends 158, 162 locatedproximal the user and/or outside the patient's vasculature. In suchinstance, it may be desirable for proximal edge 190 of the inner sheath104 to pass through the vasculature along the exterior curved segmentand the distal edge 186 of the inner sheath 104 to pass through theinterior segment. If so, the user would navigate the inner sheath 104with the indicators 138, 142, 146 aligned with the exterior segment ofthe curved vascular portion.

The indicators 138, 142, 146 in FIG. 6 are depicted as a three solidlines between the ends 158, 162 on the exterior surface of the innersheath 104, wherein the three lines are separated by indicators 112 and116. However, each of the three indicators may not be a solid line. Forexample, one or more of the indicators may alternatively include aseries of broken lines, a series of dots, a series of lines and dotsand/or a combination of lines, dots and other characters that arepositioned in alignment with the longitudinal axis of the inner sheath104 and/or in alignment with the proximal beveled edge 190 or distalbeveled edge 186 of ends 158, 162. Additionally, the outer sheath mayhave multiple indicators aligned with the longitudinal axis of the innersheath 104. For example, the inner sheath 104 may include one type ofindicator positioned along its longitudinal axis that aligns with theproximal beveled edge 190 and another type of indicator positioned alongits longitudinal axis that aligns with the distal beveled edge 186.Furthermore, the inner sheath 104 may include a third type of indicatorpositioned along its longitudinal axis that aligns with anotherreference point for one of the ends 158, 162. For example, the thirdtype of indicator may indicate the mid-point of the face 174 of one ofthe ends 158, 162.

It may also be preferable for the indicator 112, 116 and/or one set (orpair) of marks 120″, 124″, 126″, 130″ from each of the indicators 112,116 on the inner sheath 104 to be aligned with the indicators 138, 142,146 of the inner sheath 104. Aligning the indicator 112, 116 and/or oneset (or pair) of marks 120″, 124′, 126″, 130″ with the indicator 138,142, 146 on the inner sheath 104 in conjunction with the indicator 134on the outer sheath 108 allows the user to quickly see the rotationalposition of the inner sheath 104, the possible rotational alignment ofthe inner sheath 104 and outer sheath 108, and the linear position ofthe inner sheath 104 with respect to the outer sheath 108. That is, thecombination of indicators 112, 116 with at least one of the indicators138, 142, 146 on the inner sheath 104 in conjunction with the indicator134 on the outer sheath 108 allows the user to determine whether thedistal ends 154, 162 (or 158) of the inner sheath 104 and outer sheath108 are both linearly and rotationally aligned. This may be particularlyhelpful to the user of the sheath set 100 when navigating the sheath set100 through a curved portion of the vasculature, as discussed above, sothe user knows that the distal beveled edge of the inner and outersheaths will pass along the interior portion of the curved vasculature,as opposed to the exterior curved portion.

Referring to the sheath set 100 depicted in FIG. 2, the sheath setincludes a portion of the inner sheath 104 located within the outersheath 108 such that the beveled distal end 162 (not shown) of the innersheath 104 is linearly aligned with the distal end 154 of the outersheath 108 as indicated by the alignment of indicator 112 (on the innersheath 104) with the proximal end 150 of the outer sheath 108.Specifically, the proximal end 150 of the outer sheath 108 is locatedbetween the mark 120 and mark 124 of indicator 112 on the inner sheath,thereby indicating that the beveled distal end 162 of the inner sheath104 is located within the outer sheath 108, is at the distal end 154 ofthe outer sheath, and is not extending beyond the distal end 154 of theouter sheath 108. Additionally, when the inner sheath 104 is locatedwithin the lumen of the outer sheath 108 and both marks 120 and 124 ofindicator 112 on the inner sheath indicator 112 are visible to the user,then the indicator 112 indicates to the user that the end 162 of theinner sheath 104 is not linearly aligned with the end 154 of the outersheath 108 and the end 162 of the inner sheath 104 is located proximallyof the end 154 of the outer sheath 108 and potentially within the outersheath 108. Furthermore, when the inner sheath 104 is located within thelumen of the outer sheath 108 and neither marks 120 nor 124 of indicator112 on the inner sheath indicator 112 are visible to the user, then theindicator 112 indicates to the user that the end 162 of the inner sheath104 is not linearly aligned with the end 154 of the outer sheath 108 andthe end 162 of the inner sheath 104 is protruding beyond the end 154 ofthe outer sheath 108.

Continuing to refer to FIG. 2, the indicator 138 of the inner sheath 104is also aligned with the indicator 134 of the outer sheath 108, therebyindicating that the distal beveled edge 186 of end 162 of the innersheath 104 is rotationally aligned with the distal beveled edge 178 ofend 154 of the outer sheath 108. That is, the beveled distal end 162 ofthe inner sheath 104 is both linearly and rotationally aligned with thebeveled distal end 154 of the outer sheath 108, such that the beveleddistal end 162 of the inner sheath 104 is located within the outersheath and not extending beyond the distal end 154, and the distalbeveled edge 186 of end 162 of the inner sheath 104 is rotationallyaligned with the distal beveled edge 178 of end 154 of the outer sheath108.

Knowing the linear and rotational orientation of the inner sheath 104and outer sheath with respect to one another, a user may advance thesheath set 100 in this aligned configuration over a lead and insertsheath set 100 into a patient's vasculature to separate tissuesurrounding the lead. That is, the user may concurrently advance theinner sheath 104 and outer sheath 108 over the end of the lead outsideof the patient and into the patient's vasculature in such alignedposition. Once the sheath set 100 contacts the tissue, the user mayrotate and/or advance the inner sheath 104 beyond the distal end 154 ofthe outer sheath 108 to separate tissue surrounding the lead using theface 174 and/or edges 186, 190 of the beveled distal end 162. Thebeveled distal end 162 of the inner sheath 104 may be retracted backinto the outer sheath 108 by the user, and potentially realign the innerand outer sheaths, such that the sheath set 100 is further advanced inunison over the lead and deeper into the vasculature. The user may thenagain rotate and/or advance the inner sheath 104 beyond the distal end154 of the outer sheath 108 to create additional separation of thetissue surrounding the lead using the face 174 and/or edges 186, 190 ofthe beveled distal end 162. This process of concurrently advancing, inunison, the inner sheath 104 and outer sheath 108 over the lead and intothe patient's vasculature in such aligned position, then rotating and/oradvance the inner sheath 104 beyond the distal end 154 of the outersheath 108, and followed by retraction of the inner sheath 104 into theouter sheath 108 may be repeated until the desired amount of tissue hasbeen separated from the lead. The outer sheath 108 can also be advancedin front of the inner sheath 104 to aid in separation of lead fromtissue; for example, when the tissue is directly attached to the lead,it is possibly more difficult to dilate than tissue radially positionedaround the lead but unattached to the lead. Accordingly, it may beadvantageous to advance either end 150 or end 154 or both ends into thetissue and initiate dilation prior to introducing either end 158 or end162 of the inner sheath to completing the dilation of the tissuesurrounding and/or attached to the lead.

As discussed above, when navigating the sheath set 100 through a curvedportion of a patient's vasculature, it may be desirable for the beveleddistal edge 186 of the inner sheath 104 and the beveled distal edge 178of the outer sheath to pass through the vasculature along the interiorcurved segment and the beveled proximal edge 190 of the inner sheath 104and the beveled distal edge 182 of the outer sheath to pass through thevasculature along the exterior curved segment. And the indicator of thepresent disclosure allow the user to know the linear and rotationalalignment of the inner sheath 104 and the outer sheath 108 as the sheathset advances through the vasculature, thereby minimizing the likelihoodof rupturing the vasculature, particularly as the sheath set 100advances through a curved section of the vasculature.

A number of variations and modifications of the disclosure may be used.For example, the end 158 of the inner sheath 104 may be inserted intothe outer sheath 108 and aligned with its end 154. If so, the indicator116, along with its marks 126, 126′, 126″, 130, 130′, and 130″, on theinner sheath 104 would be aligned with the end 150 of the outer sheath108. Also, when the end 158 of the inner sheath 104 is inserted into theouter sheath 108, the indicator 134 of the outer sheath 108 and theindicator 146 of the inner sheath 104 will be aligned when the innersheath and outer sheath are rotationally aligned. Another variation ofthe disclosure may include inserting a beveled distal end 158, 162 ofthe inner sheath 104 into the outer sheath 108 such that one of thebeveled distal ends 158, 162 aligns with the non-beveled end 150 of theouter sheath.

It may also desirable for the user of the sheath set 100 to utilize bothends 158, 162 of the inner sheath 104 during a procedure for separatingtissue from a lead in the event that one of the ends 158, 162 becomesdull during the procedure and thereby, potentially becoming lesseffective in separating tissue. Accordingly, a user may leave the outersheath 108 in the patient's vasculature while removing the inner sheath104 completely therefrom and switching the ends 158, 162 of the innersheath 104 that are inserted into the outer sheath 108 during theprocedure by inserting the alternate end back into the outer sheath 108.The indicator of the present disclosure allows the user to do so quicklyand effectively because the indicator 112, 116, 138, 146 is the same forboth halves of the inner sheath 104, both ends 158, 162 are equallydistant from the center of the inner sheath 104, and both ends 158, 162have the same or similar configuration.

It may also be possible for both halves of the inner sheath 104 to use asingle indicator similar to indicator 112, 116 to indicate the alignmentof the ends 158, 162 of the inner sheath 104 with the end 154 of theouter sheath 108. For example, if the single indicator is located at thecenter (with respect to both ends) of the inner sheath 104 and includestwo triangular shaped marks spaced apart and facing one another, then auser will be able to align that indicator with the end 150 of the outersheath 108 and know that either end 158 or end 162 of the inner sheathis located within the end 154 of the outer sheath.

It would be possible to provide for some features of the disclosurewithout providing others. For example, the inner sheath may only haveone beveled end rather than two beveled ends to separate tissue. If so,some of the indicator of the present disclosure may be omitted.

In the appended figures, similar components and/or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a letter thatdistinguishes among the similar components. If only the first referencelabel is used in the specification, the description is applicable to anyone of the similar components having the same first reference labelirrespective of the second reference label.

The present disclosure, in various aspects, embodiments, and/orconfigurations, includes components, methods, processes, systems and/orapparatus substantially as depicted and described herein, includingvarious aspects, embodiments, configurations embodiments, subcombinations, and/or subsets thereof. Those of skill in the art willunderstand how to make and use the disclosed aspects, embodiments,and/or configurations after understanding the present disclosure. Thepresent disclosure, in various aspects, embodiments, and/orconfigurations, includes providing devices and processes in the absenceof items not depicted and/or described herein or in various aspects,embodiments, and/or configurations hereof, including in the absence ofsuch items as may have been used in previous devices or processes, e.g.,for improving performance, achieving ease and/or reducing cost ofimplementation.

The foregoing discussion has been presented for purposes of illustrationand description. The foregoing is not intended to limit the disclosureto the form or forms disclosed herein. In the foregoing Summary forexample, various features of the disclosure are grouped together in oneor more aspects, embodiments, and/or configurations for the purpose ofstreamlining the disclosure. The features of the aspects, embodiments,and/or configurations of the disclosure may be combined in alternateaspects, embodiments, and/or configurations other than those discussedabove. This method of disclosure is not to be interpreted as reflectingan intention that the claims require more features than are expresslyrecited in each claim. Rather, as the following claims reflect,inventive aspects lie in less than all features of a single foregoingdisclosed aspect, embodiment, and/or configuration. Thus, the followingclaims are hereby incorporated into this Detailed Description, with eachclaim standing on its own as a separate preferred embodiment of thedisclosure.

Moreover, though the description has included description of one or moreaspects, embodiments, and/or configurations and certain variations andmodifications, other variations, combinations, and modifications arewithin the scope of the disclosure, e.g., as may be within the skill andknowledge of those in the art, after understanding the presentdisclosure. It is intended to obtain rights which include alternativeaspects, embodiments, and/or configurations to the extent permitted,including alternate, interchangeable and/or equivalent structures,functions, ranges or steps to those claimed, whether or not suchalternate, interchangeable and/or equivalent structures, functions,ranges or steps are disclosed herein, and without intending to publiclydedicate any patentable subject matter.

1. A sheath set for insertion into a blood vessel, the sheath setcomprising: an outer sheath comprising a proximal end, a beveled distalend, a lumen between the proximal end and the beveled distal end, anexterior surface, and a longitudinal axis, wherein the beveled distalend forms a beveled proximal edge portion with the exterior surface ofthe outer sheath and a beveled distal edge portion with the exteriorsurface of the outer sheath, wherein the outer sheath further comprisesa rotational position indicator on the exterior surface of the outersheath and along the longitudinal axis of the outer sheath, wherein therotational position indicator is longitudinally aligned with the beveleddistal edge portion; and an inner sheath comprising a first beveled end,a second beveled end, a center between the first beveled end and thesecond beveled end, an exterior surface, and a longitudinal axis, theinner sheath located at least partially within the lumen of the outersheath, wherein the first beveled end forms a first proximal edgeportion with the exterior surface of the inner sheath and a first distaledge portion with the exterior surface of the inner sheath, wherein thesecond beveled end forms a second proximal edge with the exteriorsurface of the inner sheath and a second distal edge with the exteriorsurface of the inner sheath, wherein the first proximal edge portion andthe second proximal edge are proximate the center relative to the firstdistal edge portion and the second distal edge, respectively, whereinthe inner sheath further comprises a rotational position indicator onthe exterior surface of the inner sheath and along the longitudinal axisof the inner sheath, wherein the rotational position indicator islongitudinally aligned with the first distal edge and the second distaledge, and a first indicator on the exterior surface of the inner sheath,wherein the first indicator indicates the first beveled end of the innersheath is linearly aligned with the beveled distal end of the outersheath when the first indicator is linearly aligned with the proximalend of the outer sheath, and a second indicator on the exterior surfaceof the inner sheath, wherein the second indicator indicates the secondbeveled end of the inner sheath is linearly aligned with the beveleddistal end of the outer sheath when the second indicator is linearlyaligned with the proximal end of the outer sheath.
 2. The sheath set ofclaim 1, wherein the beveled distal end of the outer sheath is tapered.3. The sheath set of claim 1, wherein the first beveled end and thesecond beveled end of the inner sheath are tapered.
 4. The sheath set ofclaim 1, wherein first indicator is at least one pair of indicators. 5.The sheath set of claim 4, wherein the at least one pair of indicatorscomprises two markings comprising a space therebetween, wherein thespace indicates the first beveled end of the inner sheath is linearlyaligned with the beveled distal end of the outer sheath when theproximal end of the outer sheath is linearly aligned with the space. 6.The sheath set of claim 5, wherein the at least one pair of indicatorsis longitudinally aligned with the rotational position indicator on theexterior surface of the inner sheath.
 7. The sheath set of claim 5,wherein the two markings comprising a shape.
 8. The sheath set of claim7, wherein the two markings are the same shape.
 9. The sheath set ofclaim 8, wherein the two markings are mirror images of the same shapewhen located on the inner sheath.
 10. The sheath set of claim 1, whereinthe first indicator comprises one or more sets of indicators.
 11. Thesheath set of claim 10, wherein the inner sheath further comprises acircumference, and wherein each of the one or more sets of indicatorsare positioned evenly around the circumference of the inner sheath. 12.A sheath set for insertion into a blood vessel, the sheath setcomprising: an outer sheath comprising a proximal end, a beveled distalend, a lumen between the proximal end and the beveled distal end, anexterior surface, and a longitudinal axis, wherein the beveled distalend forms a beveled proximal edge portion with the exterior surface ofthe outer sheath and a beveled distal edge portion with the exteriorsurface of the outer sheath, wherein the outer sheath further comprisesa rotational position indicator on the exterior surface of the outersheath and along the longitudinal axis of the outer sheath, wherein therotational position indicator is longitudinally aligned with the beveleddistal edge portion; and an inner sheath comprising a first beveled end,a second beveled end, a center between the first beveled end and thesecond beveled end, an exterior surface, and a longitudinal axis, theinner sheath located at least partially within the lumen of the outersheath, wherein the first beveled end forms a first proximal edgeportion with the exterior surface of the inner sheath and a first distaledge portion with the exterior surface of the inner sheath, wherein thesecond beveled end forms a second proximal edge with the exteriorsurface of the inner sheath and a second distal edge with the exteriorsurface of the inner sheath, wherein the first proximal edge portion andthe second proximal edge are proximate the center relative to the firstdistal edge portion and the second distal edge, respectively, whereinthe inner sheath further comprises a rotational position indicator onthe exterior surface of the inner sheath and along the longitudinal axisof the inner sheath, wherein the rotational position indicator islongitudinally aligned with the first distal edge and the second distaledge, and an indicator on the exterior surface of the inner sheath andlocated at the center, wherein the indicator indicates the first beveledend of the inner sheath is linearly aligned with the beveled distal endof the outer sheath when the indicator is linearly aligned with theproximal end of the outer sheath, and wherein the indicator indicatesthe second beveled end of the inner sheath is linearly aligned with thebeveled distal end of the outer sheath when the indicator is linearlyaligned with the proximal end of the outer sheath.
 13. The sheath set ofclaim 12, wherein the indicator on the inner sheath is at least one pairof indicators.
 14. The sheath set of claim 13, wherein the at least onepair of indicators comprises two markings comprising a spacetherebetween, wherein the space indicates the first beveled end of theinner sheath is linearly aligned with the beveled distal end of theouter sheath when the proximal end of the outer sheath is linearlyaligned with the space.
 15. The sheath set of claim 14, wherein the atleast one pair of indicators is longitudinally aligned with therotational position indicator on the exterior surface of the innersheath.
 16. The sheath set of claim 12, wherein the inner sheath furthercomprises a circumference, wherein the indicator on the inner sheathcomprises one or more multiple sets of indicators, and wherein each ofthe sets of indicators are positioned evenly around the circumference ofthe inner sheath. 17-20. (canceled)
 21. The sheath set of claim 14,wherein the two markings are the same shape.
 22. The sheath set of claim21, wherein the two markings are mirror images of the same shape whenlocated on the inner sheath.
 23. The sheath set of claim 12, wherein thebeveled distal end of the outer sheath is tapered.
 24. The sheath set ofclaim 12, wherein the first beveled end and the second beveled end ofthe inner sheath are tapered.